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Last word of lines

 
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# 8  
Old 01-31-2005
Awk processes the BEGIN section before trying to open the file.
Code:
$ rm file1

$ awk 'BEGIN{print "before"}{print "during"}END{print "after"}' file1
before
awk: fatal: cannot open file `file1' for reading (No such file or directory)

If your file is empty, then both the BEGIN and END sections are preocessed.
Code:
$ touch file1

$ awk 'BEGIN{print "before"}{print "during"}END{print "after"}' file1
before
after

There only one condition where the END section is processed but the BEGIN section is not processed: you have miss-spelled "BEGIN".
# 9  
Old 02-01-2005
Thanks,

Got it.
What happened was my script was
BEGIN {} {}
I was printing something in the second brace which now comes in the scope of file, thats why it was not printing when the file was empty.

But now i have another problem.
Can i print variables in BEGIN clause.
because on combining the 2 braces my variables are not printing.

My script is:
awk -f file.awk a=xyz b=xyz file.txt
# 10  
Old 02-01-2005
Code:
awk -v a=xyz 'BEGIN{print "before"; print a}{print "during"}END {print "after"}'  file1

# 11  
Old 02-01-2005
Yes,

I am doing the same thing.
awk -v a=xyz 'BEGIN{print "before"; print a}{print "during"}END {print "after"}'

This doesn't print the variable a;

But on doing
awk -v a=xyz 'BEGIN{}{print "before"; print a}{print "during"}END {print "after"}'
or
awk -v a=xyz 'BEGIN{print "before"}{print a}{print "during"}END {print "after"}'

i.e. taking variable printing block outside of BEGIN scope it prints.
# 12  
Old 02-01-2005
Use the -v option to set a variable before the BEGIN section is processed...
Code:
$ awk -v a=xyz 'BEGIN{print "before a=" a}'
before a=xyz

You can also set a variable before each input file...
Code:
$ echo "line1" > file1

$ awk -v a=xyz 'BEGIN{print "before a=" a}{print "during a=" a}' a=123 file1
before a=xyz
during a=123

# 13  
Old 02-02-2005
Thanks got it,

Mine awk doesn't support -v option.
I had to use nawk.

How is nawk different from awk.
 
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